Acute Carecommon
A 32-year-old woman is brought in after her car left the road and struck a tree at speed. She is alert and cold to touch. Blood pressure 84/52 mmHg, pulse 126/min, respiratory rate 30/min, oxygen saturation 93% on 15 L/min. The seatbelt has left a band of bruising across the left chest. The chest wall moves symmetrically. Breath sounds are absent on the left and the percussion note there is reduced. The trachea is central, the neck veins are flat and the heart sounds are normal. Which one of the following best explains her hypotension?